We plan to develop the capacity for prolonged lung preservation by the adaptation and application of methods available and to be developed, utilizing control of ionic composition and osmotic/oncotic pressures, and employing hypothermia, hyperbaria and perfusion. With current knowledge, our ability to manipulate immunologic responses is inadequate to pursue clinical lung transplantation as anything but an investigative endeavor. Expected developments in applying specific immunologic manipulations (enhancement and/or tolerance induction) should permit the therapeutic application of lung transplantation. However, since both of these modalities depend on time-consuming pretreatment of the recipient, the availability of prolonged organ preservation will be essential to permit their use.